I heard Scarred Lands was being cancelled. It may be just a rumor.
Dont go the route of the Forgotten Realms unless you want tons of crunch and fluff. It's big, it's been developed for years, and unless you want all that as a new DM, I wouldnt start there. I have been running games the Forgotten Realms since its beginning, I love it, but theres alot of stuff to work with.
As far as Necromancer games goes, the bulk of their stuff as of late seems to be Mini-Campaigns and the Wilderlands campaign material.
As a new DM, you couldnt go wrong with any of the above mini-campaigns (modules) that I mentioned.
I should mention that Lost City of Barakus begins at 1st level, The Grey Citadel at 5th, and the Vault of Larrin Kar at 4th. I assume (although maybe incorrectly) you will want to start a new game with 1st level characters, so Barakus might be good for you.